Dry ice sublimes at -78°C at atmoshperic pressure. From what I have seen a dot3aa (is that the right standard?) cylinder has a lower working temperature of -20°C. I would be cautious of the cylinder getting cold and cracking due to brittle fracture.

Technically, oxygen is not flammable, either, nor can it "explode". It is an oxidizer, and will provide oxygen to a fire, but there needs to be a fuel of some sort in order to have such a thing happen.

Derek.
The prices fpr compressed gasses and the hazmat fees has risen astronomucally in the last 12 months. The current best price I can find around town is at a fire extinguisher service co. The welding gas places are just too expensive to fool with right now. Since a 5 lb cylinder will last a while I haven't had to fill any lately but am aware it is gonna hurt when I do. You can thamk mr Obama and the DOT for this little issue. Hazmat background checks are not cheap and every one is paying the cost of that due to 9/11. Sorry I dont have concrete prices, but I use non medical grade gasses because they are much cheaper than medical grade helium, argon or CO2.
Bob

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What do you mean "no Kidneys"???, WTF now I gotta drink less beer...
Join the Automation sub forum in Electric brewing for a discussion of components and control systems. I did!!!!

Not to thread jack, but do any of you have an adapter to do co2 canister to co2 canister transfers? I have a 20#, 5#, and 4#, and would like to use the 20# to refill the smaller ones. Any idea if what parts I need?

To answer your question, it is possible, but I think you would need to remove the valve to do it, and that can be dangerous itself depending on your skill and knowledge of compressed gas cylinders. You would need to measure (in weight) the dry ice, and not exceed the bottle rating.

That said, you should be able to find a used 5 or 10 lb bottle on craigslist for around $50... more if it includes a regulator.
Take that puppy to your nearest welding shop and exchange it for a new, filled tank (doesn't matter if it's out of date as long as it's NOT a rented tank) for exchange.
I pay $11 for each 5 lb exchange, and the tanks I get look brand new. I understand it's only $20 or so to upgrade from a 5 to 10 lb., and the fills are only a couple dollars more.

Im jealous, up here I've searched everywhere and the cheapest I can find is 40$ n change for a 5# and I just mean refill...

What about paintball? You guys have those stores around I assume? Wouldn't be too hard to addapt a large paintball co2 tank to your reg, and (at least around here) paintball refills are pretty cheap.
There is also fire extiguisher stores. Never tried them, but I understand they could be a good contact.
Good luck!

Rbeckett, where do you get your info? I don't see any evidence of price spikes due to any of the reasons you mention. Seems like local price gouging to me.